Author: Robert Hyatt
Date: 08:10:17 11/24/02
Go up one level in this thread
On November 24, 2002 at 10:08:06, Ulrich Tuerke wrote: >On November 23, 2002 at 00:57:57, Anthony Cozzie wrote: > >>The discussion on verified null move pruning has got me thinking about my >>qsearch. Right now zappa does simple-stupid qsearch: captures and recaptures, >>and I'm thinking about adding some things. If I have a better q-search it may >>be possible to move to straight R=3, which would be faster than the current >>R=2/3 (Heinz). So I am considering adding: >> >>1. Pawn Promotions. It would be very easy to add some sort of "generate white >>pawn promotions". Usually there would be none, but this could be determined >>quickly by a bitboard and (for those of us smart enough to use bitboards . . . . >>hehehe) >> >>2. Check evasion. Right now if one of the captures puts the King in check in >>qsearch, zappa just stops. >> >>3. A Horizon zone. For example, Search() would call horizon() which would call >>QSearch(). In the horizon zone, Zappa would also search checks and killer >>moves. > >How about >4. Check generation. For example, you could generate checking moves in >quiescence provided some conditions are fullfilled (e.g. close enough to >horizon, checked king standing risky, ...). > > >> >>Secondly, what are people's opinions on SEE versus futility pruning in QSearch? >>I was using SEE up until recently, when I did some experiments and decided >>Qsearch was working better. Of course, I may just have bugs in my SEE. >> >>I'll probably try most or all of this stuff anyway, but I'm curious what other >>people's views on this are. >> >>anthony I've mentioned this before, but in Cray Blitz, and some very early crafty versions, I had a three-zone search, rather than the current two-zone search. Zone one was normal. Zone two was selective and included mainly tactical moves such as checks, captures, moves that contain some sort of threat (found by null-move search) and so forth. Zone three was q-search, although in CB and early Crafty I did do check evasion if the same side was in check in all q-search plies so that any mate found would be forced... In Cray Blitz we also generated checks in certain cases, but not nearly as many as we generated in zone two, the "connector" between a normal search and the pure quiescence search...
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